March 2005 Reviewed by Anthony Di Marco	Audio Research Corporation MP1 Multichannel Preamplifier

Description Model: MP1 Price: $6995 USD Dimensions: 19"W x 6.97"H x 15"D Weight: 20.4 pounds Warranty: Three years parts and labor Features Class-A, fully balanced dual-differential circuit All-FET circuitry with unity-gain buffers between stages and a double-buffered output Massive, fully regulated power supplies with two transformers Modular plug-in boards with gold-plated, gas-tight connectors

Features (cont'd) Large vacuum-fluorescent display with 0.75"-tall readout Low-noise, high-transconductance J-FETS for all audio circuits Local FET constant-current stabilization for each audio stage Fully DC-coupled audio circuit uses servo stabilization for low offset and subsonic control Ten wideband and high-headroom audio regulators use constant-current source stabilization Balanced (XLR) and single-ended inputs and outputs Customizable at the factory for using five-channel sources in four-speaker surround systems Natural or black finish Optional handles

What do you do after you’ve fallen for the infectious sound of Audio Research Corporation’s 150M.5 multichannel power amplifier and made it your reference? Do you go to Disney World? No. You jump at the opportunity to evaluate the company’s new MP1 multichannel preamplifier ($6995). According to David Gordon, ARC’s manager of North American sales, the MP1 and 150M.5 constitute ARC’s answer to the audiophile looking for peerless performance in stereo and multichannel applications. And so the day came when the same black MP1 that Jeff Fritz had written about in last October’s "Surrounded" column showed up on my doorstep.

Family resemblance

The MP1 is lighter than the 150M.5, but strikes a pose similar to that of its power-amp cousin: a conservatively functional aluminum chassis that, according to ARC, reduces the electromagnetic interference that can add noise to the audio signal. Also like the 150M.5, the MP1 has ARC’s proprietary energy-absorbing elastomer feet, which suppress mechanical vibrations.

At 19"W by 15"D and almost 7"H, the 20-pound MP1 will take up more than a standard rack space. But open it up and the reasons for its size and heft are apparent. The MP1 shares with the 150M.5 a fanatical attention to detail, parts quality, and circuit design. Individual circuit boards feed signals to each of the MP1’s six channels through the same high-quality, high-current, gas-tight connections found on the 150M.5. The large power supply, which possesses as much capacitance as some home-theater receivers, sits to the left of the boards. Absent is the rat’s nest of wires common to many electronic components -- only the front-panel controls are wired. All audio signals are routed via massive, plated copper circuit traces. This, according to ARC, means less chance of RF interference, as well as a low resistance path for low-level audio signals.

One good thing about the MP1’s size is that it has a large rear panel. The very-high-quality single-ended and balanced XLR connections are surrounded by enough space to accommodate the meatiest fingers. I had no problem tightening Analysis Plus locking RCA cables or negotiating the large cannon connections of ARC’s Litzlink XLR cables. It’s not uncommon for an audio component with a fully balanced topology to have a higher noise floor in unbalanced mode. I noted a fair amount of hiss when using unbalanced connections between the MP1 and 150M.5. ARC recommends using balanced connections; when I did, noise was effectively reduced to a faint whisper.

The MP1’s front panel is all business. To the right of an immense vacuum-fluorescent display are two rows of six buttons each for controlling input switching, volume, power, and mute. The buttons are sized, contoured, and spaced just right for the average index finger to press, while their small number and uniform placement make it easy to feel for the right selection in the dark. The large green display is a model of simplicity and visual clarity. The large (0.75" tall) numbers are readable across three cities, much less my 17’ living room. The user can choose among six levels of intensity and off.

The MP1’s remote is simple and straightforward, its well-shaped and -positioned buttons making up for its lack of backlighting.

Setup

I appreciate gear that’s been designed with attention to ergonomics. It’s easy to hook up cables when connections are well spaced and placed respective to my left and right, which is especially helpful when making connections blindly. A nice feature of the MP1 is the ability to connect both unbalanced and balanced connections on one input. This allowed me to use the MP1’s Multi 3 input to connect my Esoteric DV-50 universal player’s front two channels balanced and the remaining center and surround channels unbalanced, which gave me the best result for stereo and multichannel listening. It also cut down on the number of cables I needed.

The MP1 lacks an internal pink-noise generator for balancing channel gain. Receivers use tone generators. Because the MP1 works in the analog domain, its calibration is relative to a source component’s analog output. I calibrated the MP1 via my Esoteric DV-50 universal player with 5.1-channel audio reference signals from Digital Video Essentials.

Calibrating gain was simple. The MP1’s Adjust function scrolls through each channel, while Volume Down reduces unity gain. Many products approach calibration this way, but that doesn’t mean I have to like it. A subwoofer usually requires a 10dB increase of gain in my room. I accomplished this with the MP1 by cutting all channels by 15dB, then raising each channel to a 75dB reference. This gave me an extra 5dB of headroom for soundtracks that required further tweaking.

The MP1 performed flawlessly except for one annoyance. Whenever I unmuted the MP1’s output quickly after switching inputs, my speakers emitted a frightening snap. The fact that Jeff Fritz had not experienced this suggested an issue with my setup. It was never determined exactly what the problem was.

Enduring affection

The MP1 enhanced the natural, effortless quality I’d heard from ARC’s 150M.5. Gone were the McCormack MAP-1’s slight electronic veil and subtle detachment across frequencies. The MP1’s sound was seamlessly integrated, from the lowest bass to the most effervescent highs. Nothing about the sound even hinted that electronics were at work.

High frequencies were infused with unbelievable air and grace. The prodigious highs in Se7en and the shriek of the Nasgul in the fabulously well-produced The Lord of the Rings: The Return of the King (Platinum Series Special Extended Edition) were tender yet powerful in their presentation. When the subtle atmospheric cues in chapter 17 of Se7en are preserved this well, the true condition of Sloth is more immediate, with greater foreboding. Similarly, the cleaner and more extended the high frequencies, the more terrifying is Gandalf’s run-in with the Witch King (chapter 45) without going brittle or edgy.

What made the ARC sound sweet was not warmth or euphoria but its limitless extension and harmonic integrity. Wonderful high frequencies descended into a naturally rich and weighty midrange. Daniel Lanois’s velvety vocals on "Sometimes," from Shine [CD, Anti 86661], felt so real that listening to this album in the dark was a joyously spine-chilling experience.

It wasn’t only the MP1’s midrange palpability that made it so enjoyable, but also the way it placed elements in the soundstage. Voices and instruments were positioned with precision but not too much of it. Where some lesser electronics drop instruments and voices in place with manmade surgical precision, the MP1 layered elements organically across and to the front and back of the plane of the front speakers. Everything overlapped like soft, fluffy clouds in a blue sky on a spring day. While the clouds have clear, obvious outlines, their transitions aren’t razor sharp. The MP1’s presentation was not one of manufactured order; rather the experience was heightened by a picture-perfect collage of sounds. The arrangement of the image appeared, and the truthfulness of the music’s timbre sounded right.

When a component sounds neutral, it is transparent and revealing of everything pumped through it. It wasn’t the MP1’s multichannel performance that captivated me, but the way it handled two-channel media. While well-recorded multichannel recordings such as Bucky Pizzarelli’s Swing Live [DVD-Audio, Chesky CHDVD222] and Neil Young’s Harvest Moon [SACD, Reprise 9362-48100-9] sounded articulate and open, less accomplished stereo recordings, such as Tinderstick’s "A Marriage Made in Heaven," from Curtains [CD, London 524344], and Mandalay’s "It’s Enough Now," from Solace [CD, V2 27094], made my spine jump out of my back. What won me over was the way the MP1 handled the bittersweet strings and vocals in those recordings.

That special something

The MP1 didn’t completely outclass my McCormack MAP-1 ($2395) -- the McCormack is one fantastic piece of gear. Pound for pound, the McCormack’s smaller chassis is built as well as the ARC’s, and the MAP-1 uses similar heavy-gauge RCA connections. These are not low-cost samples soldered onto the circuit board and sticking through a hole in the chassis -- they’re bolted on, to be capable of supporting the heaviest cables. The MAP-1’s heavy-gauge steel enclosure inspires the sort of confidence roused by very few home-theater products, most of which aren’t built for the long haul. The MAP-1 even challenges the almost-three-times-as-expensive ARC with McCormack’s ingenious Ambience Retrieval Mode (ARM), which can create convincing and balanced 5.1 surround images from two-channel sources.

Inside the boxes the differences are more obvious. A single large circuit board routes the McCormack’s six channels, while the ARC has independent boards for each channel. The McCormack’s internal layout is very clean, the power supply sizable; the ARC’s class-A design uses a larger power supply and a ton of top-shelf components. The McCormack’s single-ended design requires separate paths for signal and ground, while the ARC’s dual-differential, balanced circuit uses positive and negative legs and an independent ground.

The McCormack has a smooth, slightly cool sound with an involving sense of speed and timing. What it lacks is that last ounce of harmonic warmth, that last iota of detail that contributes to a note’s sweetness. Directly compared to the ARC MP1, the McCormack MAP-1 sounded slightly mechanical and electronic. The ARC, on the other hand, defined naturalness. It not only reproduced sounds with perfect pitch and pacing, it did so with an elegance that suggested a very transparent circuit. What the MP1 did not do was trade transparency for enjoyment.

The McCormack MAP-1 is less diplomatic with poor recordings. While it doesn’t bludgeon the listener with faithfully reproduced recording flaws, it doesn’t shelter the listener either. This is especially true in the upper midrange, where the McCormack can sound thin and uninvolving with many low-quality pop recordings. Like the ARC 150M.5 amplifier, the MP1 provided insight into a recording’s quality without causing listening fatigue. No matter how bad the recording, the MP1 pulled all of the harmonic structure from the music, effectively presenting even poorly recorded music with as much of its innate magic as possible.

Parting is such sweet sorrow

The last few months have been an epiphany for me. Before the 150M.5, I had had very little experience with Audio Research Corporation or its products. Now I can’t take my ears off them. The MP1 and 150M.5 are reference-caliber components for audiophiles whose affection for music trumps all else. If you want to hear natural, involving music without playing critic, these are the components for you. Together, the 150M.5 and MP1 can rally all the power and authority required for an exciting home-theater or music experience.

Manufacturer contact information:

Audio Research Corporation
3900 Annapolis Lane North
Plymouth, MN 55447-5447, USA
Phone: (763) 577-9700
Fax: (763) 577-0323

Website: www.audioresearch.com

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